Defoslimod is an analogue of lipopolysaccharide endotoxin-derived lipid A obtained from E. coli [1]. It was developed as an immunotherapeutic agent for the treatment of cancer. Defoslimod acts as an agonist of Toll-like receptors 2 and 4 (TLR2 and TLR4) [2]. We show the structure with chemical formula provided in the INN record for the compound (C52H100N2O20P2). PubChem CID 56841121, which claims to represent defoslimod has an extra carbon atom and two associated hydrogens (C53H102N2O20P2). But note also that the structure reported in [1] only has 51 carbon atoms.